[Elecraft] Bird 43 Wattmeter calibration

[Ron D'Eau Claire]

Where the Birds got a great reputation as the "Standard" was that every time
an FCC engineer would show up on site with the FCC test equipment to check
the output power of a transmitter, he would be carrying a Bird. 

And he was a lot 'easier going' if there was a discrepancy and the
maintenance tech drug out the station's Bird and showed that the discrepancy
was in the meters. I even had one FCC field engineer doing the annual
inspection on a ship tell me "Don't bother to change the output power. I'll
have this meter checked at the lab and give you a call if there's an issue."


That, and the incredible ruggedness of the Bird design has given them a
mystique all their own...

I have no idea how accurate they really are. As far as I'm concerned even a
20% error is meaningless in terms of range and signal strength in
communications equipment. I think the one I was hauling around on ships in
the early 1990s had a calibration sticker on it dated in the 1960's. 

Ron AC7AC
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 Lab cal is done by puting power through it measured with a known standard.
Adjustment is done with pot acessable after prying off metal label. Check at
highest and lowest and in the middle somewere. Bird rates them at +/- 5%,
but I have yet to see one better than +/- 10%. They are great for rugged
outdoor use, and peaking signal, but no one I know relies on them for
precise measurements of power.
                                                Roy AB7CE
                                                NIST RF Lab Tech